Sure, it's inherently a tech/financial/support load to maintain a special category of customer, but I don't see it as fundamentally any different from a successful company managing the discontinuation of a popular product. You cut off new customers, let attrition take its course for the existing ones, and take your lumps from any high-value/high-touch customers who drag their feet on moving to the new thing. It's work, but so is climbing a ladder. Do you want to elevate the company or not?